Is it permissible for me to marry another woman besides my first wife, knowing that I do not feel love towards my first wife, and would this marriage entail disobedience to my parents or injustice to my first wife or the second wife?

Familiarity between unrelated men and women, even with the intention of marriage, is a door to fitnah (temptation/strife). One who wishes to propose to a woman should approach homes through their proper doors. Abstaining from masturbation due to an unlawful relationship does not make the relationship permissible; rather, it indicates that occupying oneself helps in abandoning the unlawful. You must end your relationship with that woman. There is no objection to marrying her if you can be just between her and your first wife. A second marriage is not an injustice to the wife nor disobedience to parents if there is a need for it. Safeguarding Allah’s boundaries and lowering one's gaze from the unlawful are among the most important reasons for a husband's contentment with his wife, whereas unleashing one's gaze upon forbidden things makes him disinterested in his wife. A man may see another woman and imagine her to be better than his wife, then he strives to marry her, and once his wish is granted, flaws appear, and he regrets it.